Process for making paper half stock



Patented Mar. 31,1925.

' UNITED STATES.

I 1,531,319 PATENT OFFICE.

nma'rmn s. summnns, or roar HURON, MICHIGAN.

PROCESS FOR. MAKING PAPER HALF STOCK.

No Drawing.

To all whmriit may comem:

Be it known that I, BERTRAND S. S M- ms,'a citizenof the United States, residing denser paper, and the like.

at Port Huron, county of St. Clair, and State of Michigan, have invented a new and useful Process for Producing Paper Half Stock, of which the following is. a specifica-.

tion.

M. inventionrelates particularly to the r uction of-a "aper half stock suitable or the making of high grade white papers, such as cigarette paper, banknote paper, con. It is required thatthese papers shall be of absolute uniformity of texture, of a requisite degree of toughness, free from unreduced. woody fibers and specks, which fibers and specks not only spoil the appearance of the pa er but break its continuity, making it wea and useless for the purposes intended. Such papers have hitherto been made from linen stock,

usually linen rags, and high I grade mill recent waste. The supply of these materials in ears has been much less than the deman causing a great, shortage in these pa ers and greatly increased price therefor.

ere is, however, available a large quantity of flax straw resulting from the linseed and flax fiber industries.- Many attempts have been made in the past to convert this material into paper half stock having the required characteristics. Owing to the physical and chemical peculiarities of flax straw, however, such attempts have not been successful, the problem being further com pl-icated by the presence in such straw of foreign material, such as weeds.

It is wellv known that this flax straw and other straws contain ligneous matter as well as: fibrous matters, and these two classes of matter have very different resisting powers to the action of agents adapted toreduce or remove the woody material. Flax is peculiarly characterized in that it contains not only the ligneous cellulose but also pecto cellulose. The fibrous portion of flaxcontains also cutooellulose with strong waxy characteristics. v The fibrous portion is. very much" less resistent to a reducing agent than isthe li eous portion; The ligneous portion of ax straw knownas shive is one of the most resistent bodies in this respect that is known. All prior attempts, therefore, to use flax straw as'a material for paper making have resulted in the presence in the paper of specks of foreign matter and un- Application filed January 24, 1920. .Serial No. 353,824.

reduced shive, resulting in a paper of inferlor quality both as to appearance and strength and useless for the purposes to which high grade linen papers areapplied. To my knowledge paperswhich have hitherto been produced from these straws, while sometimes of good color so far as the fibrous portion is concerned, have contained a large 'element of unreduced matter, which weakattempt to reduce ens the paper, while an" this matter has resulted in the destruction of the fibrous matter, making it impossible to make a high class sheet. To my knowledge, therefore, althou h vast supplies of material have been avai able, it has hitherto been impossible. to use them.

In carrying out my invention, I treat the.

straws having the characteristics above described by firstremoving therefrom such of the ligneous material as may be done by the usual breaking and dusting process. partially cleaned material contains a considerable portion of the shive together sometimes with a quantity of weedy material. It

I has been found impracticable toremove all integrity of the fibrous portion. For this purpose I employ a very strong solution of calcium hypochlorite,. commonly known as a bleaching powder. This hypochlorite is dissolved in water and allowed to settle. A

suflicient quantity of hypochlorite is introduced into the water to bring the solution to a density of 4 to 6 Twaddle, although this may be varied to suit'the' requirements of the material to be treated. The calclum hypochlorite solution is allowed to settle and drained ofl. lution sodium bicarbonate in excess. I prefthe fiber without injuring the strength or I then introduce into this soerably make a saturated solution of sodium bicarbonate and introduce the same into the calcium hypochlorite solution. By adding an excess of the sodium bicarbonate over the quantitv required to completely precipitate or the like hoilin g out the straw thus partmlly cleaned, and then subjecting the straw to the action. of a liquid resulting from the introduction into a sufliciently concentrated 5 solution of calcium hypochloriteof an ex cess of sodium bicarbonate.

8. The herein described process, which consists in mechanically cleaning flax bicerbonate.

straw,'or the like, boilin out the 'straw thus partially cleaned, and hen sub'ecting the straw. to the action of a liquid. resulting from the introduction into a suflieiently concentrated' solution of ch1orinous matter in an active condition of an excess of BERTRANDV s. summns.

alkaline- 

